The present invention relates to a stitch data processing apparatus for an automatic sewing machine and more particularly to an apparatus for processing stitch data of complex embroidery patterns for use in an embroidery sewing machine.
There is a conventional method of processing stitch data for an automatic embroidery sewing machine, as disclosed in U.S. Pat. No. 4,520,745, the method comprising the steps of placing a sheet representing an original figure on a tablet board, specifying points on the contour lines of the original figure using a cursor, and detecting the position data of the points so as to process the stitch data. U.S. Pat. Nos. 4,429,364 and 4,446,520, though not intended for embroidery, also disclose methods similar to what is described in U.S. Pat. No. 4,520,745.
In the aforesaid methods, however, when like embroidery patterns but different in size are formed individually, an operator must specify the points on the contour lines using the cursor after processing an original figure for each size. Accordingly, there is a problem that the operation of specifying the points takes a rather long time.
U.S. Pat. No. 4,526,116 discloses a method of automatically processing stitch data by picking up an original embroidery picture drawn on a sheet by means of a television camera. However, this method still poses a problem in that, because the stitching order is automatically determined in this method, it is impossible to voluntarily set up the direction (seam direction), in which embroidery thread extends to form a pattern by satin stitches.
U.S. Pat. No. 4,660,484 also discloses a method comprising picking up the original embroidery picture using an optical scanner, storing the coordinate data thus obtained as pattern data, and adding data of stitching order to the pattern data. In this method, however, because the coordinate data obtained through the optical scanner is directly stored as the pattern data, accurate coordinate data can not be obtained in case that the original embroidery picture is an embroidery pattern to be formed on a workcloth. Moreover, in this method because only the same embroidery as the original embroidery picture can be formed, the original embroidery picture will have to be processed again when part of it is modified.
On the other hand, Japanese Patent Application Laid Open No. 75085/84 discloses a stitch data processing apparatus comprising an image sensor for reading the external shape of workcloth, an input tablet board, a stylus pen, and a CRT. In this stitch data processing apparatus, the external shape of the workcloth and the position specified by the stylus pen are displayed on the CRT and stitching data for carrying out stitching, along the external shape of the workcloth is processed through the stylus pen operated by an operator. However, the technique of making embroidery has not been taken into consideration in the method.